The Applicant has developed over the years, weaving machines for alternately laying catalyzed resin wetted fiberglass strands within respective right angle sets of uniformly spaced, open-ended intersecting slots within the upper face of a weaving form by driving reciprocating carriages mounted on rails via rotating wheels across the top of the form bearing said slots. Such machines are represented by Applicant's U.S. Pat. Nos. 3,772,126 issued Nov. 13, 1973 and 5,074,950 issued Dec. 24, 1991. In the machine of U.S. Pat. No. 5,074,950, a horizontal base plate supports hydraulic cylinders whose projectable and retractable piston rods suspend a running bar having horizontal apertures through which the fiberglass strands pass. After passage across the form, the running bar is dropped to force the wetted strands into aligned slots. Detents engage the strands at each side of the open slots. The carriages reciprocate across the form and resin tanks bearing resin, wet the fiberglass strands prior to weaving with the strands wrapped about the periphery of three laterally adjacent spaced, spaced parallel tension bars within the tank. Subsequently, the form is inverted, the wet fiberglass strands are gravity dropped into intersecting slots of a lower mold and, the resin impregnated strands are compression molded into a formed open grating of generally rectangular, elongated form. While such apparatus provides highly dense and very strong fiberglass grating, the time and expense in manufacturing such grating significantly increases the cost thereof.
In recent years, the Applicant has formed such fiberglass reinforced molded grating of first and second sets of mutually parallel, interlocking fiberglass reinforced molding resin bars with such bars extending transversely to one another and intersecting at right angles. One set is formed of bearing bars of rectangular cross section positioned in vertically upright position, laterally spaced from each other. The upper edge of the bearing bars is provided with inverted, U-shaped notches or grooves at longitudinally spaced positions. The notches include oppositely directed, downwardly and outwardly oblique slots terminating at their upper ends, adjacent the upper edge of the bearing bars, in upwardly and outwardly diverging oblique cam surfaces. A second set of tie bars or cross bars of inverted U-shaped cross section, each include a horizontal base portion and a pair of downwardly and outwardly diverging legs of a thickness generally equal to the width of the diverging slots within the upper edges of the bearing bars, are respectively received in the slots. The legs of the cross bars at longitudinally spaced positions are provided with rectangular locking notches extending from the free ends of the legs upwardly of a width generally equal to the thickness of the bearing bars and have a height which is less than the vertical height of the tie bars.
To assemble the grating, the tie bars are forced downwardly at the locking notches into the inverted U-shaped notches formed within the upper edge of the bearing bars. Cam surfaces deflect the oblique legs of the cross bars to momentarily resiliently deform the legs to cause the portions of the legs at the locking notches to snap into the oblique slots of the inverted U-shaped notches within the bearing bars. The first and second sets of bars are therefore mechanically interlocked and are maintained in such position due to the resiliency of the legs of the inverted U-shaped cross bars. Such fiberglass grating is disclosed in Applicant's U.S. Pat. No. 4,760,680 issued Aug. 2, 1988.
While such fiberglass grating formed of interlocked pultruded fiberglass grating bars, is of reduced cost compared to that of the compression molded fiberglass grating of U.S. Pat. Nos. 3,772,126 and 5,074,950, the manual assembly of the tie bars to the underlying bearing bars and the notching of respective bars to achieve that action, requires significant manual labor and is time consuming.
It is therefore a primary object of this invention to provide an improved apparatus for automatically or semi-automatically forming a fiberglass grating of interlocked pultruded fiberglass grating bars, in which a set of underlying bearing bars are arranged for movement longitudinally over a table or other horizontal conveyor, which array of bearing bars are incremented in precise, equal steps to permit between steps, notching of the inverted U-shaped notches within the upper edges of the vertically upright rectangular cross sectional bearing bars, wherein, subsequent to the notching of a series of aligned notches within all of the bars of a respective set, adhesive is applied to the faces of the notches facing a right angle positioned cross bar, forcibly camming a tie bar into notch engagement with the set of bearing bars and the partially formed grating incremented, advancing the set of bearing bars and partially formed grating structure, from a notching station to the tie bar die press coupling station to effect interlocked engagement between an overlying tie bar and the series of bearing bars of the first set into the inverted U-shaped adhesive applied notches within the upper edge of those bearing bars.
It is a further object to provide such apparatus which permits acceptance and positioning of a plurality of bearing bars for a given set of selective thickness and height while maintaining the bars in precise laterally spaced alignment, wherein the set of bearing bars are advanced incrementally over precise distances which may be varied depending upon the desired spacing between the right angle, intersecting tie bars, which couple the bearing bars together, and wherein the bearing bars are held firmly in momentary fixed position during the notching, liquid adhesive application, and tie bar intercoupling stages of the grating manufacture.
With the foregoing objects and features and such other objects and features which may become apparent from the specification, the invention will be understood from the following description taken in conjunction with the accompanying drawings in which like numerals designate like parts.